This invention is directed to a chair control mechanism for a pedestal-type office chair having a knee-tilt seat.
An object of this invention is a knee-tilt control mechanism which provides a high initial torque and spring rate for resisting rearward tilting movement of the chair seat and in which the restoring torque increases at less than a linear rate as the chair seat is tilted backward.
Another object of this invention is a simple, compact, knee-tilt control mechanism which can be easily concealed so that it does not detract from the aesthetic appearance of the office chair.
Another object of this invention is a knee-tilt chair control mechanism which utilizes an elastomeric spring which is offset rearwardly from the axis of tilting of the chair seat.
Another object of this invention is a knee-tilt chair control mechanism which utilizes the linearly-increasing restoring torque of an elastomeric spring to provide a less than linear restoring torque to the chair seat.
Another object of this invention is a knee-tilt chair control mechanism which utilizes the engagement of an arm connected to the chair seat with a non-radial extending cam surface connected to an elastomeric spring to reduce the effective moment arm of the spring as the angle of rearward tilt of the chair seat increases.
Another object of this invention is a simplified and compact pre-torque adjustment mechanism for an elastomeric spring which permits a large angular degree of twist of the spring upon a relatively short linear movement of the adjusting device.
Another object of this invention is a mechanism which permits the occupant of the chair to adjust the chair seat to a more conventional seat angle in its unoccupied condition.
Other objects of the invention may be found in the following specification, claims and drawings.